In modern motor vehicles, exhaust gas turbochargers with so-called variable turbine geometries are increasingly employed, wherein the power output and the response characteristics can be adapted to various operating conditions (for example load change). To achieve this, adjustable non-rotating guide blades are located in the turbine inlet or in the turbine housing, which blades are usually mounted together in a blade bearing ring. Through different operating temperatures at a front side exposed to the hot gas flow and a back side of the blade bearing ring facing away from said front side, uneven heat expansion of the latter can occur, as a result of which it can get warped for example and as a result threaten smooth-running mounting of the guide blades in the blade bearing ring.
From DE 103 37495 A1 a generic exhaust gas turbocharger for a combustion engine is known wherein at least one threaded pin is provided which fastens a blade bearing ring carrying individual guide blades to a bearing housing of the exhaust gas turbocharger on a side facing away from the flow channel. The aim of this is to achieve simplified assembly on the one hand and the omission of parts in the flow channel interfering with the flow.
From DE 10 2004 062564 A1 a blade bearing ring of a charging device is known, which in terms of material is designed for high engine outputs. To this end, the blade bearing ring is characterized by a component of 1-6% by weight of an alloy element or a plurality of these elements such as tungsten, cobalt, niobium, rhenium, molybdenum, tantalum, vanadium, hafnium, yttrium, zirconium or the like. The aim here is to achieve more preferably a high creep resistance and high strength at temperatures above 850° C.